If you have a trauma first aid kit:
For life-threatening bleeding from an arm or leg and a tourniquet is NOT available
For life-threatening bleeding from the knee, shoulder or groin:
Pack (stuff) the wound with bleeding control gauze (also called hemostatic gauze), plain gauze, or a clean cloth and then apply pressure with both hands.
Open the clothing over the bleeding wound. Wipe away any pooled blood.
Pack (stuff) the wound with bleeding control gauze (preferred), plain gauze or clean cloth.
Apply steady pressure with both hands directly on top of the bleeding wound. Push down as hard as you can. Continue pressure until relieved by medical responders.